A robotic submarine has continued its search for the missing Malaysia Airlines flight on the seabed of the southern Indian Ocean.

The mini-sub was deployed late on Tuesday, but was forced to resurface due to a technical issue, officials said. It has since been redeployed.

The data downloaded from the mini-sub on Wednesday had "no significant detections", Australian officials add.

Flight MH370 went missing on 8 March with 239 people on board.

Air traffic controllers lost contact with it over the South China Sea while it was en route from Kuala Lumpur to Beijing.

Based on satellite data, officials believe it ended its flight thousands of kilometres off course, in seas west of the Australian city of Perth.

However, so far not a single piece of debris from the jet has been found.

'No detections'

On Monday, the US Navy's Bluefin-21 robotic submarine was sent on its first mission to search the sea floor for wreckage after signals believed to be consistent with "black box" flight recorders were detected.

Image copyrightReutersImage caption
Other ships and aircraft are scouring the search area for debris

But the drone exceeded its operating limit of 4,500m (15,000ft) and built-in safety features returned it to the surface. "No objects of interest were found," Australia's Joint Agency Co-ordination Centre (JACC) said.

The mini-sub was again deployed on Tuesday from the Australian Defence Vessel Ocean Shield.

It was forced to resurface on Wednesday morning to rectify an unspecified technical issue and redeployed, JACC said.

"Initial analysis of the data downloaded this morning indicates no significant detections," it said.

The 5m-long Bluefin-21 can create a sonar map of the sea floor.

The US Navy has estimated that it could take the unmanned submarine from six weeks to two months to scan the search zone.